Physicians and Specialties in the Veterans Health Administration’s Community Care Network

This cross-sectional study of data from the US Veterans Health Administration examines the availability of services provided through community care networks by specialty and clinical characteristics.


Additional Notes on Data Sources
We used the VHA's Corporate Data Warehouse (CDW) and Provider Profile Management System (PPMS) to identify physicians who participated in the VHA community care network as of December 31 st , 2019.Participation was defined as having an active contract with the VHA and did not depend on having VHA enrollees as patients.The PPMS data also indicated whether the physician was accepting new patients.We limited our sample to physicians with a valid national provider identifier (NPI) listed in the National Plan and Provider Enumeration System (NPPES) Registry.We identified providers who submitted at least one Medicare claim in 2019 from the Centers for Medicare & Medicaid Services' (CMS) Provider Utilization and Payment Data and Quality Payment Program.This data source also included data on characteristics of both physicians and their panels of Medicare beneficiaries.CMS assigns patients to physician panels based on Medicare claims received during that year.Additionally, we obtained Quality ratings and practice size data for clinicians participating in CMS' Quality Payment Program (QPP).Provider practice location was obtained from the Provider Enrollment, Chain, and Ownership System (PECOS) which identified the states in which each provider is licensed to practice medicine.
Physicians were the primary population and were identified by NPI.We limited our sample to only physicians within the 50 states and District of Columbia, excluding U.S. territories.Advanced practice providers were excluded because specialty is not identified for many of these clinicians.We also excluded specialties where expertise was provided without a patient encounter or the specialty was not for adult medicine: pathology, radiology, pediatrics, pediatric specialty care.We categorized physicians into 34 distinct specialty categories; specialties with fewer than 1,000 providers nationwide were grouped as "Other" (eMethods Table ).A sample selection flow chart is provided in the eMethods Figure.

Detailed Description of Study Variables
Our primary outcome was network breadth, defined as the number of physicians who participated in VHA community care divided by the total number of Medicare participating physicians.Physician characteristics included specialty, gender, state(s) of licensure, year of medical school graduation, which is a correlate of number of years in clinical practice, practice size (number of clinicians), whether the physician is located in a rural area or healthcare professional shortage area, and final score under the Merit-based Incentive Payment System (MIPS).Physicians' MIPS scores range from 0-100, with higher scores denoting better overall performance in each of four categories (quality, cost, improvement activities, and promoting interoperability).We also identified physicians who received positive payment adjustments under MIPS, defined as a final score greater than 75.
Medicare Patient characteristics included mean age, percent male, average payments per beneficiary-year, mean Hierarchical Condition Category (HCC) risk score, and the total number of Medicare beneficiaries seen by the physician.HCC risk scores are a measure of projected future health spending based on patient demographics, prescription drug categories, and if comorbidities are present.The mean Medicare patient has a risk score of 1.0; patients that are healthier than average will have an HCC score below one and those that are less healthy than average would have a score above one.

Analytic Approach
Our unit of analysis was the individual physician.We linked Medicare and VHA data by physician NPI.We described the characteristics of physicians and patients who did and did not participate in the VHA community care network.Differences between the two groups were assessed using standardized mean differences (SMDs).A SMD value of less than or equal to 0.1 was considered an indication of similarity while a SMD of greater than 0.1 indicated that differences between the two groups were unlikely to have occurred by chance.